* [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S
@ 2020-03-30 7:59 Balamuruhan S
2020-03-30 8:13 ` Christophe Leroy
2020-07-30 12:50 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Balamuruhan S @ 2020-03-30 7:59 UTC (permalink / raw)
To: mpe
Cc: ravi.bangoria, jniethe5, Balamuruhan S, paulus, sandipan,
naveen.n.rao, linuxppc-dev
Data Cache Block Invalidate (dcbi) instruction implemented back in
PowerPC architecture version 2.03. But as per Power Processor Users Manual
it is obsolete and not supported by POWER8/POWER9 core. Attempt to use of
this illegal instruction results in a hypervisor emulation assistance
interrupt. So, ifdef it out the option `i` in xmon for 64bit Book3S.
0:mon> fi
cpu 0x0: Vector: 700 (Program Check) at [c000000003be74a0]
pc: c000000000102030: cacheflush+0x180/0x1a0
lr: c000000000101f3c: cacheflush+0x8c/0x1a0
sp: c000000003be7730
msr: 8000000000081033
current = 0xc0000000035e5c00
paca = 0xc000000001910000 irqmask: 0x03 irq_happened: 0x01
pid = 1025, comm = bash
Linux version 5.6.0-rc5-g5aa19adac (root@ltc-wspoon6) (gcc version 7.4.0
(Ubuntu 7.4.0-1ubuntu1~18.04.1)) #1 SMP Tue Mar 10 04:38:41 CDT 2020
cpu 0x0: Exception 700 (Program Check) in xmon, returning to main loop
[c000000003be7c50] c00000000084abb0 __handle_sysrq+0xf0/0x2a0
[c000000003be7d00] c00000000084b3c0 write_sysrq_trigger+0xb0/0xe0
[c000000003be7d30] c0000000004d1edc proc_reg_write+0x8c/0x130
[c000000003be7d60] c00000000040dc7c __vfs_write+0x3c/0x70
[c000000003be7d80] c000000000410e70 vfs_write+0xd0/0x210
[c000000003be7dd0] c00000000041126c ksys_write+0xdc/0x130
[c000000003be7e20] c00000000000b9d0 system_call+0x5c/0x68
--- Exception: c01 (System Call) at 00007fffa345e420
SP (7ffff0b08ab0) is in userspace
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
---
arch/powerpc/xmon/xmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
---
changes in v3:
-------------
Fix Christophe's review comments and rebase it on latest mpe's merge
tree,
* mention the dcbi obsolete statement based on Power processor
users manual in commit message.
* make #ifdef in a more simple way.
changes in v2:
-------------
Fix review comments from Segher and Michael,
* change incorrect architecture version 2.01 to 2.03 in commit
message.
* ifdef it out the option `i` for PPC_BOOK3S_64 instead to drop
it and change the commit message accordingly.
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index ea303b7e4e29..7b62d5dcc4a1 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1808,7 +1808,7 @@ static void cacheflush(void)
catch_memory_errors = 1;
sync();
- if (cmd != 'i') {
+ if (cmd != 'i' || IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {
for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
cflush((void *) adrs);
} else {
base-commit: 1ad3b5ebe084246ad593a22707cd91ef6418c31e
--
2.24.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S
2020-03-30 7:59 [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S Balamuruhan S
@ 2020-03-30 8:13 ` Christophe Leroy
2020-07-30 12:50 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Christophe Leroy @ 2020-03-30 8:13 UTC (permalink / raw)
To: Balamuruhan S, mpe
Cc: ravi.bangoria, jniethe5, paulus, sandipan, naveen.n.rao, linuxppc-dev
Le 30/03/2020 à 09:59, Balamuruhan S a écrit :
> Data Cache Block Invalidate (dcbi) instruction implemented back in
> PowerPC architecture version 2.03. But as per Power Processor Users Manual
> it is obsolete and not supported by POWER8/POWER9 core. Attempt to use of
> this illegal instruction results in a hypervisor emulation assistance
> interrupt. So, ifdef it out the option `i` in xmon for 64bit Book3S.
>
> 0:mon> fi
> cpu 0x0: Vector: 700 (Program Check) at [c000000003be74a0]
> pc: c000000000102030: cacheflush+0x180/0x1a0
> lr: c000000000101f3c: cacheflush+0x8c/0x1a0
> sp: c000000003be7730
> msr: 8000000000081033
> current = 0xc0000000035e5c00
> paca = 0xc000000001910000 irqmask: 0x03 irq_happened: 0x01
> pid = 1025, comm = bash
> Linux version 5.6.0-rc5-g5aa19adac (root@ltc-wspoon6) (gcc version 7.4.0
> (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #1 SMP Tue Mar 10 04:38:41 CDT 2020
> cpu 0x0: Exception 700 (Program Check) in xmon, returning to main loop
> [c000000003be7c50] c00000000084abb0 __handle_sysrq+0xf0/0x2a0
> [c000000003be7d00] c00000000084b3c0 write_sysrq_trigger+0xb0/0xe0
> [c000000003be7d30] c0000000004d1edc proc_reg_write+0x8c/0x130
> [c000000003be7d60] c00000000040dc7c __vfs_write+0x3c/0x70
> [c000000003be7d80] c000000000410e70 vfs_write+0xd0/0x210
> [c000000003be7dd0] c00000000041126c ksys_write+0xdc/0x130
> [c000000003be7e20] c00000000000b9d0 system_call+0x5c/0x68
> --- Exception: c01 (System Call) at 00007fffa345e420
> SP (7ffff0b08ab0) is in userspace
>
> Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/xmon/xmon.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> ---
> changes in v3:
> -------------
> Fix Christophe's review comments and rebase it on latest mpe's merge
> tree,
> * mention the dcbi obsolete statement based on Power processor
> users manual in commit message.
> * make #ifdef in a more simple way.
> changes in v2:
> -------------
> Fix review comments from Segher and Michael,
> * change incorrect architecture version 2.01 to 2.03 in commit
> message.
> * ifdef it out the option `i` for PPC_BOOK3S_64 instead to drop
> it and change the commit message accordingly.
>
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index ea303b7e4e29..7b62d5dcc4a1 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -1808,7 +1808,7 @@ static void cacheflush(void)
> catch_memory_errors = 1;
> sync();
>
> - if (cmd != 'i') {
> + if (cmd != 'i' || IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {
> for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
> cflush((void *) adrs);
> } else {
>
> base-commit: 1ad3b5ebe084246ad593a22707cd91ef6418c31e
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S
2020-03-30 7:59 [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S Balamuruhan S
2020-03-30 8:13 ` Christophe Leroy
@ 2020-07-30 12:50 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2020-07-30 12:50 UTC (permalink / raw)
To: mpe, Balamuruhan S
Cc: ravi.bangoria, jniethe5, paulus, sandipan, naveen.n.rao, linuxppc-dev
On Mon, 30 Mar 2020 13:29:54 +0530, Balamuruhan S wrote:
> Data Cache Block Invalidate (dcbi) instruction implemented back in
> PowerPC architecture version 2.03. But as per Power Processor Users Manual
> it is obsolete and not supported by POWER8/POWER9 core. Attempt to use of
> this illegal instruction results in a hypervisor emulation assistance
> interrupt. So, ifdef it out the option `i` in xmon for 64bit Book3S.
>
> 0:mon> fi
> cpu 0x0: Vector: 700 (Program Check) at [c000000003be74a0]
> pc: c000000000102030: cacheflush+0x180/0x1a0
> lr: c000000000101f3c: cacheflush+0x8c/0x1a0
> sp: c000000003be7730
> msr: 8000000000081033
> current = 0xc0000000035e5c00
> paca = 0xc000000001910000 irqmask: 0x03 irq_happened: 0x01
> pid = 1025, comm = bash
> Linux version 5.6.0-rc5-g5aa19adac (root@ltc-wspoon6) (gcc version 7.4.0
> (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #1 SMP Tue Mar 10 04:38:41 CDT 2020
> cpu 0x0: Exception 700 (Program Check) in xmon, returning to main loop
> [c000000003be7c50] c00000000084abb0 __handle_sysrq+0xf0/0x2a0
> [c000000003be7d00] c00000000084b3c0 write_sysrq_trigger+0xb0/0xe0
> [c000000003be7d30] c0000000004d1edc proc_reg_write+0x8c/0x130
> [c000000003be7d60] c00000000040dc7c __vfs_write+0x3c/0x70
> [c000000003be7d80] c000000000410e70 vfs_write+0xd0/0x210
> [c000000003be7dd0] c00000000041126c ksys_write+0xdc/0x130
> [c000000003be7e20] c00000000000b9d0 system_call+0x5c/0x68
> --- Exception: c01 (System Call) at 00007fffa345e420
> SP (7ffff0b08ab0) is in userspace
Applied to powerpc/next.
[1/1] powerpc/xmon: Use `dcbf` inplace of `dcbi` instruction for 64bit Book3S
https://git.kernel.org/powerpc/c/81a413259a224f0d1783c41a74f18864d4f3d67e
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-03-30 7:59 [PATCH v3] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S Balamuruhan S
2020-03-30 8:13 ` Christophe Leroy
2020-07-30 12:50 ` Michael Ellerman
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